Outbound Glossary
TAM
The total market in theory. Useful for a board slide, nearly useless for a campaign, because almost none of it is in the market today.
Total addressable market is the total revenue available if you captured the entire market you have defined. Counting every company that could in principle buy is one way to estimate it, and it is usually what outbound teams mean when they say the word. It is the number used to argue that an opportunity is big enough to pursue.
For outbound it misleads, because at any moment only a small fraction of a market is actually deciding anything. The number that drives a campaign is how many companies show a reason to act this quarter, which is almost always smaller and far more actionable than the TAM.